import { expect, it, describe } from "bun:test";
import { gc as gcTrace, withoutAggressiveGC } from "harness";

const getByteLength = str => {
  // returns the byte length of an utf8 string
  var s = str.length;
  for (var i = str.length - 1; i >= 0; i--) {
    var code = str.charCodeAt(i);
    if (code > 0x7f && code <= 0x7ff) s++;
    else if (code > 0x7ff && code <= 0xffff) s += 2;
    if (code >= 0xdc00 && code <= 0xdfff) i--; //trail surrogate
  }
  return s;
};

describe("TextDecoder", () => {
  it("should not crash on empty text", () => {
    const decoder = new TextDecoder();
    gcTrace(true);
    const fixtures = [new Uint8Array(), new Uint8Array([]), new Buffer(0), new ArrayBuffer(0), new Uint16Array(0)];

    for (let input of fixtures) {
      expect(decoder.decode(input)).toBe("");
    }

    // Cause a de-opt
    try {
      decoder.decode([NaN, Symbol("s")]);
    } catch (e) {}

    // DOMJIT test
    for (let i = 0; i < 90000; i++) {
      decoder.decode(fixtures[0]);
    }

    gcTrace(true);
  });
  it("should decode ascii text", () => {
    const decoder = new TextDecoder("latin1");
    gcTrace(true);
    expect(decoder.encoding).toBe("windows-1252");
    gcTrace(true);
    expect(decoder.decode(new Uint8Array([0x41, 0x42, 0x43]))).toBe("ABC");
    gcTrace(true);

    // hit the SIMD code path
    const result = [
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
      72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33, 72, 101, 108, 108, 111, 32, 87, 111, 114, 108, 100, 33,
    ];
    gcTrace(true);
    expect(decoder.decode(Uint8Array.from(result))).toBe(String.fromCharCode(...result));
    gcTrace(true);
  });

  it("should decode unicode text", () => {
    const decoder = new TextDecoder();
    gcTrace(true);
    const inputBytes = [226, 157, 164, 239, 184, 143, 32, 82, 101, 100, 32, 72, 101, 97, 114, 116];
    for (var repeat = 1; repeat < 100; repeat++) {
      var text = `❤️ Red Heart`.repeat(repeat);

      var bytes = Array.from({ length: repeat }, () => inputBytes).flat();
      var decoded = decoder.decode(Uint8Array.from(bytes));
      expect(decoder.encoding).toBe("utf-8");
      expect(decoded).toBe(text);
      gcTrace(true);
    }
  });

  describe("typedArrays", () => {
    var text = `ABC DEF GHI JKL MNO PQR STU VWX YZ ABC DEF GHI JKL MNO PQR STU V`;
    var bytes = new TextEncoder().encode(text);
    var decoder = new TextDecoder();
    for (let TypedArray of [
      Uint8Array,
      Uint16Array,
      Uint32Array,
      Int8Array,
      Int16Array,
      Int32Array,
      Float32Array,
      Float64Array,
      DataView,
      BigInt64Array,
      BigUint64Array,
    ]) {
      it(`should decode ${TypedArray.name}`, () => {
        const decoded = decoder.decode(new TypedArray(bytes.buffer));
        expect(decoded).toBe(text);
      });
    }

    it("DOMJIT call", () => {
      const array = new Uint8Array(bytes.buffer);
      withoutAggressiveGC(() => {
        for (let i = 0; i < 100_000; i++) {
          const decoded = decoder.decode(array);
          expect(decoded).toBe(text);
        }
      });
    });
  });

  it("should decode unicode text with multiple consecutive emoji", () => {
    const decoder = new TextDecoder();
    const encoder = new TextEncoder();
    gcTrace(true);
    var text = `❤️❤️❤️❤️❤️❤️ Red Heart`;

    text += ` ✨ Sparkles 🔥 Fire 😀 😃 😄 😁 😆 😅 😂 🤣 🥲 ☺️ 😊 😇 🙂 🙃 😉 😌 😍 🥰 😘 😗 😙 😚 😋 😛 😝 😜 🤪 🤨 🧐 🤓 😎 🥸 🤩 🥳 😏 😒 😞 😔 😟 😕 🙁 ☹️ 😣 😖 😫 😩 🥺 😢 😭 😤 😠 😡 🤬 🤯 😳 🥵 🥶 😱 😨 😰`;
    gcTrace(true);
    expect(decoder.decode(encoder.encode(text))).toBe(text);
    gcTrace(true);
    const bytes = new Uint8Array(getByteLength(text) * 8);
    gcTrace(true);
    const amount = encoder.encodeInto(text, bytes);
    gcTrace(true);
    expect(decoder.decode(bytes.subarray(0, amount.written))).toBe(text);
    gcTrace(true);
  });

  it("should respect fatal when encountering invalid data", () => {
    const decoder = new TextDecoder("utf-8", { fatal: true });
    expect(() => {
      decoder.decode(new Uint8Array([0xc0])); // Invalid UTF8
    }).toThrow(TypeError);
  });

  it("should not trim invalid byte sequences when fatal is false", () => {
    const buf = Buffer.from([77, 97, 110, 32, 208, 129, 240, 164, 173]);
    const received = new TextDecoder("utf-8").decode(buf);
    const expected = "Man Ё\ufffd";
    expect(received).toBe(expected);
  });

  it("should trim when stream is true", () => {
    const buf = Buffer.from([77, 97, 110, 32, 208, 129, 240, 164, 173]);
    const received = new TextDecoder("utf-8").decode(buf, { stream: true });
    const expected = "Man Ё";
    expect(received).toBe(expected);
  });

  it("constructor should set values", () => {
    const decoder = new TextDecoder("utf-8", { fatal: true, ignoreBOM: false });
    expect(decoder.fatal).toBe(true);
    expect(decoder.ignoreBOM).toBe(false);
  });

  it("should throw on invalid input", () => {
    expect(() => {
      const decoder = new TextDecoder("utf-8", { fatal: 10, ignoreBOM: {} });
    }).toThrow();
  });

  it("should support undifined", () => {
    const decoder = new TextDecoder(undefined);
    expect(decoder.encoding).toBe("utf-8");
  });
});

describe("TextDecoder ignoreBOM", () => {
  it.each([
    {
      encoding: "utf-8",
      bytes: [0xef, 0xbb, 0xbf, 0x61, 0x62, 0x63],
    },
    {
      encoding: "utf-16le",
      bytes: [0xff, 0xfe, 0x61, 0x00, 0x62, 0x00, 0x63, 0x00],
    },
  ])("should ignoreBOM for: %o", ({ encoding, bytes }) => {
    const BOM = "\uFEFF";
    const array = new Uint8Array(bytes);

    const decoder_ignore_bom = new TextDecoder(encoding, { ignoreBOM: true });
    expect(decoder_ignore_bom.decode(array)).toStrictEqual(`${BOM}abc`);

    const decoder_not_ignore_bom = new TextDecoder(encoding, { ignoreBOM: false });
    expect(decoder_not_ignore_bom.decode(array)).toStrictEqual("abc");
  });
});

it("truncated sequences", () => {
  const assert_equals = (a, b) => expect(a).toBe(b);

  // Truncated sequences
  assert_equals(new TextDecoder().decode(new Uint8Array([0xf0])), "\uFFFD");
  assert_equals(new TextDecoder().decode(new Uint8Array([0xf0, 0x9f])), "\uFFFD");
  assert_equals(new TextDecoder().decode(new Uint8Array([0xf0, 0x9f, 0x92])), "\uFFFD");

  // Errors near end-of-queue
  assert_equals(new TextDecoder().decode(new Uint8Array([0xf0, 0x9f, 0x41])), "\uFFFDA");
  assert_equals(new TextDecoder().decode(new Uint8Array([0xf0, 0x41, 0x42])), "\uFFFDAB");
  assert_equals(new TextDecoder().decode(new Uint8Array([0xf0, 0x41, 0xf0])), "\uFFFDA\uFFFD");
  assert_equals(new TextDecoder().decode(new Uint8Array([0xf0, 0x8f, 0x92])), "\uFFFD\uFFFD\uFFFD");
});
